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Dry galloping of inclined cables has been shown to have a strong relation to the critical Reynolds number. This study concerns the occurrence of galloping of an elliptical cylinder at critical Reynolds numbers under normal wind and an assessment of the quasi-steady assumption on predicting these vibrations. A series of static and dynamic wind tunnel tests are carried out to measure the wind pressure on a static cylinder and displacement of a three-degree-freedom vibrating cylinder. The static aerodynamic force on the cylinder shows the occurrence of reattachment which lowers the drag coefficient and increases the lift coefficient at critical Reynolds numbers. This phenomenon gives the possibility of satisfying the across-wind galloping criterion by adversely changing the aerodynamic force with the angle of attack. Meanwhile, unsteady and steady amplitude galloping are observed in dynamic tests in a certain range of Reynolds number and angle of attack. The observations indicate that the galloping is across-wind dominated and strongly depends on the Reynolds number. Finally, quasi-steady predictions of galloping instability are compared with the observed galloping. Most of the observed occurrences of galloping are in the predicted unstable range, but several other cases for which galloping was predicted do not exhibit large vibrations. This implies that the quasi-steady assumption does not work well in predicting the galloping of elliptical cylinders at critical Reynolds numbers.

This paper presents the application of the dual analysis concept to plate bending. In this method, a same problem is analyzed parallely by a displacement and an equilibrium model. The energetic distance between these two models is the sum of both global errors and consequently, an upper bound of each of them. After an exposition of the two models, numerical examples are presented, which illustrate the high obtainable accuracy of the method.

A novel refined arctangent exponential shear deformation theory (RAESDT) is presented for analysis the mechanical behavior of both isotropic and sandwich FGM plates. Material properties are set to be isotropic at each point and varied across the thickness direction obeying to a power-law distribution of the volume fraction gradation with respect to FGM core or skins of the plate. Unlike high-order shear deformation plate theories based on five or more variables, the displacement field of the novel RAESDT using arctangent exponential variations in planed displacements were approximated by only four unknowns, satisfying naturally tangential stress-free conditions at the plate surfaces and leading to reduce computational efforts. In accordance with RAESDT and enhanced moving kriging interpolation (EMKI)-based meshfree method with a new quadrature correlation function is introduced for the numerical modeling. Numerical validations with different plate configurations, geometries, length to thickness ratios and boundaries conditions are conducted. The obtained results are compared with the corresponding solutions available in the literature showing the accuracy and efficiency of the present approach.

This paper presents an experimental investigation of stayed cable vibrations in dry-wind and rain-wind coupling hazards. To mitigate large vibrations of the cable, the use of spiral wires wrapped around the cable is proposed. By testing two cable models in a wind tunnel in dry and rain conditions for different yaw angles and wind speeds, the effectiveness of using the spiral wires to mitigate large vibrations is clarified. Finally, the paper provides a further understanding of the complex mechanism of wind-induced and rain-wind-induced vibrations. It is found that the low-frequency vortex flows in the wake play a significant role in the excitation of large responses of the cable in high wind speeds. The spiral wires dismiss these low-frequency flows and then reduce the large vibrations.